The use of battery-powered, mobile devices is becoming increasingly prevalent, such as the iPhone®, iPad® and Android® devices. Some of these devices are connected to cellular networks on Long Term Evolution (LTE) networks while others connect to the Internet using Wi-Fi networks which are also a type of cellular network. Cellular network operators need to keep up with the traffic load imposed by increasing user devices and surge in demand for higher speed, reliable connections to an increasing number of mobile users.
In large cities with hundreds of thousands of mobile devices connected to cellular networks, some fraction of devices suffer from low quality cellular connections to the base stations comprising the cellular network.
The quality of the Internet connection of mobile devices in the cell edge may be improved significantly if the mobile devices can connect to the cellular network via hot spots. Hot spots are mobile devices with higher quality connections typically located outside the cell edge. Physically, this is similar to how small cells or pico base stations improve the connection to the macro base stations, however base stations are typically fixed location, AC powered, and therefore do not have a limited battery life. Unlike cells with fixed locations, the use of hot spots can be adaptive to changes and movements of groups of users.
It is common for a mobile device with a cellular network connection to also function as a hot spot whereby other mobile devices can connect wirelessly to the cellular network via the hot spot. The advantage of the hot spot is that it relays traffic between the cellular network and the mobile devices connected to it at a better connection quality than would otherwise be available to the mobile device. For example the iPhone® running on Verizon® Wireless cellular network may act as a hot spot by providing a Wi-Fi connection to an iPad®. The cellular network connection and the hot spot connection may operate in the same frequency band or in a different frequency band.
Mobile devices are typically not allowed to connect to hot spots unless explicitly authorized by the cellular network subscriber who owns the hot spot. Since hot spots are also mobile devices with limited battery life, allowing all other public devices to connect to the hot spot without any admission control may quickly drain the batteries of hot spots or consume their available capacity when connecting to the cellular network. Typically, there is no automated admission control which will permit cell edge users to connect to hot spots of other users without the owner granting permission. Hot spots accept only mobile devices authorized by their owner less than some maximum number of connections (e.g. 3, 10, etc) to limit the amount of traffic load that they support for mobile devices within an acceptable level (e.g. 20-50% of the capacity available to the hot spot from the cellular network).
If an admission control policy based on mobile device limits were extended to include all other mobile devices using the cellular network, it may result in a large fraction of mobile device connected to the hot spots and may not end up connecting the cell edge devices which would benefit the most. Furthermore, if a large number of mobile devices were connected to hot spots, it may also trigger a large number of disconnections in the network when hot spot devices move around or hot spot devices are shut off. If there is no control on which mobile devices connect to hot spots, since hot spots are also mobile devices they may in turn connect to other hot spots leading to a large hop count in the network.
The presence of a hot spot can be broadcast to notify nearby mobile devices. Limits and reduction of the broadcast transmission power of the hot spot may reduce the number of nearby public mobile devices that may learn about and attempt to connect to the hot spot. Without additional protocols broadcast power alone does not discriminate and prioritize the cell edge users that stand to gain the most from other mobile devices that may get only a marginal improvement in connection quality.
It is desirable to create an admission control scheme for all mobile devices to hot spots that minimizes mobile battery usage of devices with hot spots, minimizes cellular network disconnections, while incentivizes owners of hot spots to share their scarce resources to achieve maximum improvement in quality of Internet connections for the mobile devices by prioritizing the cell edge.